Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden and does well: it discloses that documents are SHARED and never copied, that the first document is focused, the binding is durable, and a roster is returned. It is silent on the authorization parameter and on error/failure behavior, which are meaningful gaps for a session-creating mutation.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The purpose is front-loaded, but the text repeats the 'one-call way to start a session with documents already open' idea and the '/documents/open' cross-reference twice. Some sentences could be consolidated without loss.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a combined create-plus-open tool with no annotations and no output schema, the description covers the key behaviors an agent needs (sharing semantics, focus, empty-session case). It lacks only authorization and failure-mode detail to be fully complete.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 75%, and the description reinforces session_id semantics (client-chosen vs server-minted) and the document_ids roles beyond the schema. It adds little for include_html (already fully documented) and leaves the authorization parameter unaddressed in both schema and description.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description names a specific verb+resource (create a session and open N documents) and precisely scopes it as a combined one-call operation. It implicitly separates this from the sibling open_documents by framing it as the way to start a session with documents already open.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives concrete usage context: the web UI passes its own session_id, while an MCP/API integrator omits it and the server mints one; with no document_ids it returns an empty session. It never names the sibling open_documents or states an explicit when-not-to-use, so it stops short of full routing guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.